<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<script>
    var arr = [1,2,3,4];
    console.log(arr.toString());//1,2,3,4
    console.log(arr.join("*"));//1*2*3*4
</script>
</body>
</html>